Explosive and process for making



Patented Aug. 12, 1930 ROBERT G. WULFF, 03 L08 ANGELES, CALIFORNIAEXPLOSIVE AND PROCESS FOR MAKING No Drawing. Application. filed Harchl,

This invention relates to an explosive which is capable ofbecomingharmless within a reasonably short interval after being loadedinto a bore hole. One of the objects of this invention is to producesuch an explosivehaving the added advantage of producing less and lesscarbon monoxide the later it is fired. Other explosives of this class,the liquid oxygen explosives, produce more'and more carbon monoxide thelater they are fired, because the I oxidizing agent evaporates veryrapidly.

Another 'object 'of my invention is to produce an explosive'which may beeasily m1xed together at place of use from relatively harmless and cheapmaterials. My explosive comprises a solid oxidizing agent and a volatilecombustible. Liquid oxygen explosives comprise a volatile oxidizingagent and a fixed combustible.

An advantage of myexplosive is that the oxygen-bearing constituent" issolid, and

. the climate or the nature of the work, so as to control the rate ofevaporation. I do this by adding heavier or lighter hydrocarbons.

In my explosive, the oxidizing agent may be a chlorate or perchlorate.It may alternativelyjbe ammonium nitrate or' other nitrate, or even aperox'ide', such as calcium or barium peroxide. The combustibleis anormally gaseoushydrocarbon, such as propane or butane, preferably thelatter. Very volatile casin head gasoline or petroleum ether is alsosuitable, but pure liquefied butane is 1929. Serial No. 345,249.

preferred. Also a mixture of hydrocarbons containing butane and lighterconstituents may be used.

My explosive is produced by wetting the oxidizing agent with thecombustible to saturation, over saturation, or undersaturation, inrespect to either'the'capacity of the oxidizing agent for physicallyholding the combustible or for oxidizing it. I prefer to oversaturatethe oxidizing agent in both respects since the volatility of thecombustible soon diminishes the excess of the latter. The saturation ispreferabl' accomplished by dipping a cartridge 0 oxidizin agent, in aporous or open envelope, suc as of cloth or paper, completely into acontainer full of liquefied combustible. The oxidizing agent, nowsaturated, is then lifted out and thereafter used, as an explosive assoon sible; that is, loaded into the bore proximately within half anhour. plosive will lose its power of ex at least of exploding violently,i is attempted after a longer interval than an hour. The exact timedepends upon the tightness to which the bore hole is tamped, and otherfactors, such as the size of the bore hole hole ap- The ex-. loding orand the volatility of the combustible. While I may fire the explosivewith only a fuse or electric squib when only low explosive power isrequired, I find that for high exiplosive force it is necessary to exlode the ly a No.

mixture with a detonator, prefera 8 fulminate detonator.

Under some conditions, for instance, in hot climates, I find itadvisable to alter the composition of my explosive to the extent ofadding an" absorbent material to the oxidizing agent before mixing thecombustible therewith. Such absorbents are referably incombustible, suchas silica gel, liieselguhr, or adsorbent clay. I may use combustibleadsorbents such as activated charcoal, wood flour or, sawdust, but onlyin small percentages, that is, 5% by, weight or less of the oxidizing asposthe firing following ranges:

/ Per cent Oxidizing agent 60-95 Absorbent 1-15 Volatile combustible5-40 Proportions are intended to be varied according to the-kind of workto be done and the specific material employed.

The mixture should be so adjusted so that at the time it is tobe fired,there is no excess or deficiency of combustible with reference to theamount of oxidizing agent present.

The container necessary may or may not.

be combustible. It must allow the volatile combustible to leave thecharge as it evaporates. This may be accomplished by having a containerwith a hole near the top comlose, dlnitrotoluene, trinitrotoluene, etc.

municating to the atmosphere. It may also be done by making thecontainer wall of suitable porosity therefor, while at the same timepreferably retaining the combustible as long as it is inthe liquidphase. 7

After the mixing has once taken place, the combustible is not to behindered from evaporating except by the resence of an absorbent or'bythe resence o the tamping in the bore hole. Bot of these do notabsolutely prevent escape of the combustible. I'may use a permeablecontainer for my ex losive, however, such as a cardboard cylin er, pa erwraping, cloth bag, or even asbestos ag. The atter, while expensive, hasthe advantage that the oxidizingcharge maybe packaged and shipped,out"ofcontact with any combustible substance whatever so that'fire risk iseliminated.

In order to'diminish the hygroscopic tend-j enciesof any of my oxidizingagents, I may coat the particles thereof with any of the usualprotective coatings, such as nitro-celllpoxidizing agents may be variedas to their particle size from crystals the approximate size of a peadown to a finely round condition. In general the more finely ivided theoxidizing agent, the quicker. and more powerful will be the explosive. I

' Instead of using a singleoxidizing agent I may mix those which Ihaveenumerated, but a chlorate or peroxide should never be mixed withammonium nitrate.- I may substitute for part of expensive oxidizingagents, however, such as perchlorates, up to 50% of cheaper ones, suchas-sodium nitrate- In cases where an explosive of the maxiexplosive upto hydrocarbon liquid, such as a mixture of propane and butane, evenwith small proportions of ethane.

I claim as my invention:

1. An explosive comprising an unsealed combustible liquid more volatilethan pentane and a solid oxidizin' agent.

2. An explosive accor ing to claim 1 in which the volatile combustibleliquid is a hydrocarbon normally gaseous at atmosp eric temperature andpressure.

3. An explosive comprising a mixture of a solid oxidizing agent and aliquefied normally gaseous mixture of hydrocarbons substantially open totheatmosphere.

4. An explosive comprising a perchlorate and a liquefied normallygaseous mixture of hydrocarbons substantially open to the atmosphere'. 1

5, An explosive comprising a perchlorate,

an alkali-metal nitrate and a liquefied nor-v mally gaseous mixture ofhydrocarbons substantially open to the atmosphere.

6. An explosive comprising a solid oxidizing agent, an absorbent and asubstantial proportion of an unconfined petroleum hydrocarbon liquidmore volatile than pentane.

7. An explosive comprising a solid oxidizing agent, a non-combustibleabsorbent and a su stantial proportion of an unconfined petroleumhydrocarbon than pentane. o

8. An unsealed explosive comprising an oxidizing salt and a volatilecombustible liquid a substantial proportion of which is liquid butane.9. An. explosive having a liquefied volatile oxidizable constituent andcapable of losing. its explosive power after a few hours exposure toatmospheric temperature and pres- A liquid more volatile sure by reasonof the evaporation of its said 1 oxidizable constituent.

10. 'Anexplosive comprising a solid oxidizing agent and an initialexcess of a combustible liquid more volatile than pentane over thatrequired for complete consumption of the oxygen of the oxi plosive tionsof tem erature and pressure of being altered. as to its oxygen balanceso that more complete combustion will occur after an interval ofexposure to such atmospheric -con ditions. p

11. An explosive comprising an oxidizing salt, finely divided aluminumand a substan tial proportion of a liquid hydrocarbon more volatile thanentane. v

12. An exp osive com rising an oxidizing salt, silicagel and a sutantial proportion 'zing agent, said exeing capable at atmospheric condiasse ses of a liquid hydreeerben mere missile shim pentaneq 13. Anexpiesive eemprisin en @Xidisin 7 salt, silica gel, aluminum pew er andiiqizi bumme a 14. An explosive comprising an exidizing salt theparticles whereof have s. pretestive coating and a, substantialpmportien ef a liquid hydreeerben mere veietiie fuham penbane.

m 15. The process of making an explesive adapted to seem lose iisexplosive power under atmospheric cenditiens which com rises dipping acharge eemprisin an oxi izing ssh:

eenta-ined in a porous is ric cemteimer into a vessel centeimng asubstantial quemtisy M a liquefied mixture 05 bydmcar one more volatilethan penises, and then withdrawing said charge.

1.6..Ti1e process 0f making an expiesive capable of soon losing itsespiosive sewer umier atmospheric conditions which cemprises'wettin acharge eemprising an exidizing salt he d in a persons oonisiner, with asubstantial quensity ef-s hydmesrimnw ceuos liquid more volatile thanpentane,

In testimony whereof, I. have iwreunte set my hand at Les Angeies,California, this 2nd day ,of March, 1929.

RQBERT G. WLFF.

